Community Water System · PWS WA5390050
Twisp Town Of
Operator location Twisp, Washington - upper-third violation load (> 74 violations) with 138 EPA violations; groundwater source; 1,044 served (PWS-level, not municipal population).
- 1,044
- People served (this PWS)
- 138
- EPA violations (this PWS)
- 8
- Health-based (this PWS)
- Untested
- UCMR5 (this PWS)
Twisp Town Of standing, high SDWIS violation third
138 EPA SDWIS violations on record - upper-third violation load (> 74 violations). Corpus terciles use 29,740 systems serving 500+ (the sitemap cohort). Health-based share 6% is middle-third health share (≤ 23%). Population rank #19,049 of 29,740 among systems serving 500+.
The verdict
Twisp Town Of sits in the upper third of the sitemap cohort by violation count (138), so the tables below sample a dense compliance trail rather than a near-clean ledger. Population served is mid-pack at 1,044 (mid served population (≤ 3,309)). Health-based share is 6% (middle-third health share (≤ 23%)). No UCMR5 PFAS test appears for this system in this extract.
- #19,049 of 29,740
- Population · /systems
- #504 of 766
- Population · WA
- 138
- Total EPA violations on record
- 6%
- Health-based (MCL / treatment failure)
Population ordinals match the sitemap cohort (systems serving 500+, population_served DESC). See methodology · corpus placement.
System Details
- System Type
- Community
- Owner Type
- Local
- Connections
- 670
- County
- Okanogan
- School/Daycare
- No
- MCL Violations
- 8
- Monitoring Violations
- 130
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Nitrate | MR | 41 | 2022 |
| Coliform (TCR) | MCL | 8 | 2005 |
| Endrin | MR | 5 | 2005 |
| BHC-GAMMA | MR | 5 | 2005 |
| Simazine | MR | 5 | 2005 |
| Di(2-ethylhexyl) phthalate | MR | 5 | 2005 |
| Hexachlorocyclopentadiene | MR | 5 | 2005 |
| Atrazine | MR | 5 | 2005 |
| LASSO | MR | 5 | 2005 |
| Methoxychlor | MR | 5 | 2005 |
| Toxaphene | MR | 5 | 2005 |
| Heptachlor epoxide | MR | 5 | 2005 |
| Chlordane | MR | 5 | 2005 |
| HEXACHLOROBENZENE | MR | 5 | 2005 |
| Di(2-ethylhexyl) adipate | MR | 5 | 2005 |
| Heptachlor | MR | 5 | 2005 |
| Benzo(a)pyrene | MR | 5 | 2005 |
| Coliform (TCR) | MR | 4 | 2000 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1979 |
| Mercury | MR | 1 | 1979 |
| Chromium | MR | 1 | 1979 |
| Fluoride | MR | 1 | 1979 |
| Pentachlorophenol | MR | 1 | 2005 |
| Arsenic | MR | 1 | 1979 |
| Barium | MR | 1 | 1979 |
| Cadmium | MR | 1 | 1979 |
| Revised Total Coliform Rule | MON | 1 | 2020 |
| Selenium | MR | 1 | 1979 |
Violation Count vs. the National Corpus
Twisp Town Of has 138 recorded EPA violations, 80% of the 29,740 public water systems serving 500+ people nationwide carry fewer, and 20% carry more. 6% of this system's own violations are health-based (8 of 138), and it ranks #19,049 of 29,740 by population served among that same cohort.
EPA violations vs. the national water-system corpus
Public water systems serving 500+ people (EPA SDWIS)
138 Higher than most more violations than 80% of 29,740 water systems
the national water-system corpus, bucketed by value
Each bar is a band; taller bars hold more water systems. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source EPA SDWIS · 2026-05-15
SDWIS compliance record for Twisp Town Of
138 violations on record for WA5390050; use EPA SDWIS to confirm return-to-compliance dates and monitoring categories.
Sources: EPA SDWIS · Washington State Department of Health, Office of Drinking Water
Nationwide peers
138 violations · 1,044 served: nearest cross-state SDWIS matches.
Cross-state systems with comparable violation load
Nearest cross-state community systems (500+ served) by total SDWIS violations on record.
Cross-state systems near this population served
Nearest cross-state systems by EPA SDWIS population_served (same 500+ sitemap gate).
What to do with Twisp Town Of
Use this system's EPA-reported record as a starting filter, not a final verdict.
- See how every tracked system in Washington compares on the same EPA violation measures. Washington systems
- Check whether PFAS was detected at this system under UCMR5 testing. PFAS guide
- Find and compare another public water system by name or PWSID. Search systems
EPA SDWIS and UCMR5 figures are informational only, not a substitute for a certified lab test of your own tap water.